Various types of orthopaedic devices are known for the fixation of bone fragments. Such devices typically are used to stabilize bones by maintaining fractured bone portions in relatively fixed positions with respect to each other. The alignment and stability provided by the devices promotes the healing of fractures, allowing proper fusion to occur.
Internal fixation devices include bone screws, which are used in a variety of orthopaedic applications for fixation of bone fragments. Bone fragments may be positioned in a desired configuration, and one or more holes may be drilled and tapped across the fracture. Compression and stabilization of the bone fragments may then be effected by screwing bone screws into the holes. One limitation associated with bone screws, however, is that repositioning or adjusting the bone screws following implantation is difficult. In order to accommodate a different alignment, it is often necessary to remove the original bone screws and drill new holes for subsequent bone screw implantation.
Metal pins also are often used to stabilize bones. Similar to bone screws, metal pins may be inserted in holes drilled across bone fragments to confer stability to the bone. However, as with bone screws, removal of the pins may be required if subsequent realignment of bone portions is necessary.
Intramedullary implants are another device used for fixation of bone fragments. Such a device may be placed in the central canal of a fractured bone and locked thereto at the longitudinal ends of the device using screws. The use of intramedullary implants is very invasive, though, and the implants are difficult to manipulate once installed within the canals of bone fragments.
External fixation devices also are commonly used to stabilize bone segments. These devices employ a plurality of pins which extend through a patient's skin into holes drilled in fractured bone. Clamps are used to secure the pins to a common apparatus, which may for example take the form of a rod that is disposed generally parallel to the anatomically correct longitudinal axis of the fractured bone. The clamps in combination with the common apparatus create a rigid frame for immobilizing the fracture to promote healing.
External skeletal fixation is a preferred method of treatment for various limb deformities, injuries, and other conditions including: severe open fractures, fractures associated with severe burns, fractures requiring distraction, fractures requiring limb lengthening, arthrodesis, infected fractures, and nonunions. External fixation offers several advantages over the above-mentioned internal fixation approaches. For example, external fixation enables skeletal stabilization to be managed from a location that is generally remote from the proximity of deformity, injury, or disease, thereby permitting direct surveillance of the limb and wound during related or subsequent procedures. In addition, external fixation facilitates adjustment of fracture alignment, bone lengthening, bone compression, and fixed distraction following initial surgery. Furthermore, minimal interference with proximal and distal joints allows immediate mobilization of a wounded limb, and insertion of the fixator pins can be performed under local anesthesia.
Despite these developments, there remains a need for fixation devices with improved adjustability. In particular, there remains a need for fixation devices with improved joints and overall constructions.